Rod lenses of the type noted above are disclosed in U.S. Pat. No. 5,892,625, the disclosure of which is incorporated herein by reference. Rod lenses according to this invention are similar in certain respects to but differ in other respects from rod lenses disclosed in U.S. Pat. No. 5,892,625.
Reference is made to the description of the prior art in U.S. Pat. No. 5,892,625, from column 1, line 16, through column 2, line 61, and to the several references cited on its title page, namely U.S. Pat. No. 2,171,640, U.S. Pat. No. 3,257,902, U.S. Pat. No. 3,364,816, U.S. Pat. No. 3,799,656, and U.S. Pat. No. 4,168,882. Reference is made to the description of optical glasses and optical liquids in U.S. Pat. No.5,892,625, in column 5, lines 1 through 57.